If it is asked, “What, then, is the ruling on this matter? Is continuous fasting permissible, forbidden, or disliked?”
The answer is that scholars have differed on this matter, holding three views:
The first is that it is permissible for anyone (1) able to sustain it. This view is reported from Abd Allāh ibn al-Zubayr (2) and others among the early generations (3). Ibn al-Zubayr would fast continuously for several days. Among the arguments advanced by those who hold this view is that the Prophet (peace and blessings be upon him) fasted continuously with his Companions despite having forbidden them to do so. As related in the two Sahīh collections (4), Abū Hurayrah reported that he forbade continuous fasting and said, “I am not like you.” When they refused to stop, he continued fasting with them for one day, then another (5). This account shows that he fasted continuously with them after forbidding continuous fasting. Had his prohibition meant that it was forbidden, they would not have refused to stop, nor would he subsequently have approved their doing so.
They argued: Since they did so after his prohibition, with his knowledge and approval, it is clear that his intention was to show them mercy and ease their burden. Indeed, Ā’ishah said, “The Messenger of Allah (peace and blessings be upon him) forbade continuous fasting out of mercy for them.” Reported by both al-Bukhārī and Muslim (6).
Another group held that continuous fasting is not permissible; among them were Mālik and Abū Hanīfah